Various devices for monitoring one or more physiological functions of a subject are known. Conventional devices may enable one or more cardiovascular functions, one or more respiratory function, or other physiological functions to be monitored. Cardiovascular functions may include a heart rate, a heart rate variability, a pulse transit time, a pulse shape, and/or other cardiovascular functions. Respiratory functions may include a respiration rate, a respiratory effort, and/or other respiratory functions.
Generally, in order to monitor physiological functions of a subject, conventional devices operate typically require physical proximity and/or access to the subject. For example, cardiovascular functions may be monitored by contact (e.g., monitoring the flow of blood through blood vessels and/or arteries close to the skin of the subject, monitoring heart beats by the rise and fall of the chest, etc.), by sound (e.g., through a stethoscope, etc.), or by another mechanism that requiring physical proximity and/or access with the subject. Respiratory functions may be monitored, for instance, by measuring a flow rate of gas proximate to an airway of the subject, or by another mechanism requiring physical proximity and/or access to the subject.
The physical proximity and/or access to the subject typically required by conventional devices for monitoring physiological function may be intrusive and/or may be uncomfortable, which may, in some circumstances, preclude monitoring a subject. For example, monitoring the subject without alerting the subject may not be possible. In other cases, monitoring the subject may impair an ability of the subject to rest while being monitored. Other drawbacks with conventional devices are known.
Various measuring devices for measuring linear distances using one or more laser radars are known. Such measuring devices may generate information related to a distance or range of a target from the measuring device and/or a velocity, or range rate, of the target relative to the measuring device. This range and range rate information may be useful in a variety of settings. For the purposes of this application the term range rate refers to the rate of change in the range between the target and the measuring device.